Attachment for protractors



1. .M. I. SCHWARZ.

ATTACHMENT FOR PROTRACTORS.

APPLICATION FILED APR.25, I92!- 1,408,646. Patented Mar. 7,1922.

2 SHEETS-SHEET I.

J. M. J. SCHWARZ.

ATTACHMENT FOR PROTRACTORS.

APPL|CATTON FILED APR.25. 1921.

1,408,646. Patented Mar. 7,1922.

2 SHEETS-SHEET 2- UNITED STATES PATENT OFFICE.

ATTACHMENT FOR PROTRACTORS.

Specification of Letters Patent.

Patented Mar. 7, 1922.

Application filed April 25, 1921. Serial. No. 464,067.

To all whom it may concern:

Be it known that I, JAcoB M. J. SCHWARZ, a citizen of the United States, residing at Kewanee, in the county of Henry and State of Illinois, have invented certain new and useful Improvements in Attachments for Protractors, of which the following is a specification reference being had to the accompanying drawings.

It is the purpose of the present invention to provide a device for attachment for protractors for gauging the degree or taper of various milling cutters and the like cutting tools, and at the same time ascertain whether or not the cutter or milling .tool is true. 4

Another purpose is the provision of a device for attachment of this kind to ascertain whether or not the clearance of the cutter or milling tool "is perfectly uniform and true.

Still another purpose is the provision of a protractor of substantially the conventional construct-ion shown in the drawings, comprising a head, on which a base for supporting a cutter or 'milling tool revolubly thereon, is mounted tor sliding movement toward and from the blade of the protractor, so that the milling tool or cutter may rotate relatively to the blade, for the purpose of disclosing whether or not the cutter or tool is true, and whether or not the clearance is uniform.

A further purpose is .the provision of means for holding the base in different adjusted positions on the head of the protractor, and means for revolubly supporting the milling tool or cutter on the base.

While the design and construction at present illustrated and set 'forth is deemed preferable, it is obvious that as a result of a reduction of the invention to a more practical form for commercial purposes, the invention may be susceptible ,of'changes, and

the right to these changes is claimed, pro- Figure 1 is a perspective view of aprotract r showing the-improved att chment as applled. v

Figure 2 is a sectional view on line 2-2 of Figure 1.

Figure 3 is a sectional view on line 3-3 of Figure 1.

Figure 4 is a sectional view .on line 4- 4 of Figure 1.

Figure 5 is a view in elevation showing the attachment as applied to a protractor, with a different form of cutter mounted on the base of the attachment for gauging whether or not the cutting surface of the tool is true, and also whether or not the clearance is uniform.

Figure 6 is a diagrammatic view showing another ,form of tool cutter being measured or gauged.

Referring to the drawings, 1 designates the head of a protractor, and which coniprises the opposed side plates and the guide flanges 8. The adjacent ends of the elongated portions l- (which carry the flanges .3) are integrally connected, as shown at 5. The opposed plates 7 and 8 have cylindrical openings 9, which are concentrically inregistration, for the reception of the dial body 10. This dial body 10 has an opening 11,-an'd upon its opposite faces are suitable graduations or degree readings 12, there being an indicator or arrow 13 for indicating :the angle the head of the protractor may be set with reference to the blade.

As heretofore stated the ends of the elongated portions of the head ofthe protractor are integrally connected, therefore a slot or passage way is caused to be formed between the elongatedgportions of the head. The opposing'plates 7 and 8 are equally spaced, substantially equal .to the slot or opening or passage way between the .op- ,posed longitudinal parts of the head of the protractor. v r

A suitable scale blade 25'' is mounted in the slot between the longitudinal portions or sides of the head, and through "the opening' or space between the opposed plates 7 and 8. This scale blade is provided with a longitudinally extending groove l l, ElIlClQX- groove let sufl ieiently to hold the blade 1 ,aoaeae 15 to insure an o iierutivi r. cojlrliectii'm between the blade and the screw. it will he noted that the lug l5 is ot such, construc" tion, preferably oi. angular shape, as to prevent the screw tron] turning; re atively to the blade. A. thuinb nut .16 is threaded on the screw, and is provided with a chambered out portion 1.6", there being; aspring til" engaged in the chambered. out portion and iu terposed between its hot n and a Hat face 16 ot' the opening it or t 1e dial body. It will. be noted that by setting u p the thumb nut 11.6, the lug 15 will. tigr htei'i or pull. against one shoulder of the groove 14;. and hold the blade 25" in different adjusted positions relatively to the dial body. lt wili be noted that the dial body has an annular flange 10 which the shoulder 10 of the plate 7. Diainetricaliy opposite thumb screws 11 of sutlicient diameter to overlap the dial body are threaded into the plate 7, and act to hold the dial body in litterent adjusted positions relatively to the head, and thereby hold the blade in di 1'."- ferent positions relatively to the head. The spring 16 acts to tension the lug in the in place, but it will be noted that tJD-UfGSSlVG force or pressure on one end. or the other the blade will permit the blade to more. In other words the force or pressure is s1. ficient to overcome friction between toe parts, so that the blade may be adjusted relatively to the head and vice versa. The head of the protractor may be adjusted so as to dispose the scale blade at difierent angles relatively to the heath particularly the scale blade is movable with the dial body. In fact this adjustment can be made by loosening the thumb screws Ill.

A base 19 oi the general or coir-relational construction herein shown iounted upon and guided by the flanges 3 of the elongated parts of the protractor head. The base has a longitudinally extending channel. E20 which receives the flanges 8 oi the head. whereby the base may move toward and. from the scale blade. In Fact the base 15) may be used. as operating in the direction inward and from the scale blade. and may be reversed if desired. The base carries a thumb screw 21', which .pasLs through the wall oi the base and'biuds against one oi thev elongated portions of the head. in fart one oi the dances 3 of the head. is engaged by the shank oi the thumb screw 2i, l'or holding the base in different adjusted positions relatively to the edge of the blade.

A journal or stud 22 is mounted upon the base, and its shank 28 is threaded into the base. This journal or stud is designed to revolubly support a cutter or milling toolQ-i. the cutting teeth of which are to be gauged for the purpose of ascertaining whether or not the cutting teeth are true, and whether or not there is sullicient uuitorm clearance. Any form oi cutter or milling tool may be niountml upon the journal or stud 22, so that it may remain firmly in place and yet be pern'iitted to rotate freely, with its cutting teeth in close proximity to the edge of the scale blade.

The base l9 is designed to be reversed, when a milling tool or cutter of considerable diameter is to be gauged. The opposiuo surfaces of the walls of the head may at one end thereof have inclined shoulders, which are engaged by the flat sheet metal steel plate or wedge 25, which acts to not only hold the base 19 in position, but also to prevent springing of the various parts when the thumb screw 21 is tightened. iris wede'e or steel plate is interposed between the inclined shoulders 26 of the opposing surfaces of the opposite walls of the head andthe bottom of the channel 20 of the base. The position of the wedge or plate in this manner assists materially in holding the base 19 in position. The wedge will. act to force the base in the direction of the edge oi? the scale blade so as to position the teeth of the milling tool or cutter in their proper relative positions to the edge oi? the blade, yet not too close so as to prevent the cutter or millingtool from rotating.

When adjusting the head oi? the protractor. the thumb screws 11' may be loosened which. will permit the head to rotate or more freely upon the dial body, and as the blade is connected to the dial body by means (it the screw and thumb nut 15 and 16, the blade will move with the dial body and permit the head to more relatively to the blade. ll hcn the thumb screws 11 are loosened the head may freely rotate on the dial body, so as to set the blade at different angles acrording; to the cutter or milling tool to be gauged. After the head and the blade have been ai'ljusted, the thumb screws ll may be tightened, to hold the dial body in position and the head relatively thereto. By tightening; up the thumb nut 16, the scale blade it tightened relatively to the dial body. to insure moving thcrmvith. ln accompl'ishiin: this the lugg'lfi" pulls against one wall o i the groove ll. il'iereby tightening: the blade in the recess ill. of the dial body. In tact the edge oi the blade is drawn in cbutact with the butt om. oi the recess 27 oi the dial body, so that the blade will. more with the body.

In order to ascertain whether or not the circumference of the cutter is perfectly true or ascertain whether or not several cutters to he used in gangs) are the same diameters, or whether or not they are true, and have uniform clearance, the cutter may be placed upon the journal or stud 22, the scale blade having; been. adjusted at 90 degree angle.

The base 19 is then adjusted toward the blade, until the longest point or part of the cutter or milling tool is disposed relatively close to the edge of the scale blade. The thumb screws 11 are then tightened, to hold the head in position, and subsequently the cutter or milling tool is revolved or rotated. As the center of the stud or journal 22 remains a uniform distance from the edge of the scale blade, it may be observed and determined whether or not the cutting teeth of the cutter or milling tool are true, and whether or not there is sufficient clearance for the teeth to operate. Should any of the teeth of the cutter or milling tool touch the edge of the scale blade and prevent the milling tool or cutter to rotate, and should any of the teeth pass the edge of the scale blade too freely, or with considerable space between the teeth and the edge of the blade, it will disclose the fact that the cutter is untrue or uneven. In order that it may be said that the cutter or milling tool is operatively true, uniform diameter and operates with suflicient clearance, the edge of each flute or cutting part of the milling tool or cutter is designed'to assume a position relatively and uniformly close to the edge of the scale blade, during its arcuate travel adjacent the edge of the scale blade. The same method is employed for ascertaining whether or not the cutter will have sufficient clearance, whenoperated. In Figure 6 it is disclosed that the cutting edges of the cutter or milling tool are designed to move in a uniformly arcuate direction and relatively close to the edge of the scale blade, while the heels of the cutting edges remain at uniform distances from the edge of the blade.

When it is desired to test or gauge a cutter or milling tool for spiral flutes, the cutter or milling tool may be disposed upon the stud or journal for revoluble movement, in the same manner as heretofore mentioned, and in this case only a small part of the cutter or milling tool moves relatively close to the scale blade at one time. hen receiving such form of cutter or milling tool the entire length of the cutting edge will pass the edge of the scale blade. The same method may be followed in finding the degree of taper, or the degree of taper of any other member, with the exception that the cutter is placed upon the stud or journal, then the thumb screws 11 are loosened, the protractor head adjusted on the dial body, so that the edge of the scale blade may conform substantially to the taper of the cutter. In cases where the cutter is of larger diameter than the cutters herein shown, or from four to five inches in diameter, the base may be reversed, thereby disposing the stud or journal a considerable distance from the edge of the blade.

The invention having been set forth, whatis claimed as being useful is:

l. The combination with a protractor having a head and a scale blade, of a carriage adjustable upon said head and having a journal on which. the cutter or milling tool may be revolubly mounted with its cutting edges relative to the edge of the scale blade, to disclose whetheror not the teeth are true and uniform.

2. The combination with a protractor including a head and a scale blade, of a reversible carrier adjustable upon said head and having means for revolubly supporting a cutter, whereby its cutting edges may operate relatively to the edge of the blade, and the uniformity and clearance of the cutting edges may be ascertained.

In an attachment, the combination with a protractor comprising a head having guides and including a scale blade adjustable at different angles to the head, of a carrier adjustably engaging said guides and having means to revolubly support a cutter, whereby its cutting edges may be moved relatively to the scale blade, to ascertain the uniformity and clearance of the cutting edges.

4. The combination with a protractor including a head provided with guides and having an adjustable scale blade, of a reversible carrier adjustably engaging said guide and having means to revolubly support the cutter, whereby its cutting edges. may be moved relatively to the edges of the scale blade, to ascertain the uniformity and clearance of the cutting edges.

5. The combination with a protractor including a head provided with guides and having an adjustable scale blade, of a reversible carrier adjustably engaging said guide and having means to revolubly support the cutter, whereby its cutting edges may be moved relatively to the edges of the scale blade, to ascertain the uniformity and clearance of the cutting edges, and a wedge and a thumb screw for holding the carrier in different adjusted positions relatively to the edge of the scale blade. 1

In testimony whereof I hereunto afiix my signature.

JACOB M. J. SCHWARZ. v 

